Quesada Allué L A, Maréchal L R, Belocopitow E
Acta Physiol Lat Am. 1976;26(5):349-63.
In vivo and in vitro synthesis of chitin in Triatoma infestans was studied. For in vivo experiments, [14C] sugars were injected through the abdominal wall. Maximal incorporation of radioactivity into the cuticle was attained immediately after the ecdysis. The identification of in vivo synthesized chitin was performed by the enzymatic hydrolysis of the alkali-insoluble material from the cuticle with Helix chitinase. The main water-soluble compound obtained was N-acetylglucosamine as demonstrated by chromatographic procedures. In vitro synthesis of chitin was carried out with enzymatic crude extracts from Triatoma infestans, and UDP-N-acetylglucosamine was used as "source" of glycosyl moieties. Higher amounts of [14C] N-acetylglucosamine incorporation to chitin than those previously reported by others, were obtained. The identity of the product was confirmed in a similar way as that from in vivo synthesis. Radioactivity was also found in a liposoluble fraction concomitantly with chitin synthesis. This compound had an anionic behavior, was acid labile and had similar chromatographic properties as dolichol pyrophosphate N-acetylglucosamine obtained with pig liver extracts. Knowledge about dolichol phosphate sugars mediated glycoprotein synthesis in eukaryotes, suggests the involvement of this type of N-acetylglucosaminyl-phospholipid in macromolecule "building" even in insects.
对骚扰锥蝽体内和体外几丁质的合成进行了研究。对于体内实验，通过腹壁注射[¹⁴C]糖。蜕皮后立即实现了放射性最大程度地掺入表皮。通过用螺旋几丁质酶对表皮中碱不溶性物质进行酶水解来鉴定体内合成的几丁质。如色谱分析程序所示，得到的主要水溶性化合物是N-乙酰葡糖胺。用骚扰锥蝽的酶粗提物进行几丁质的体外合成，并使用UDP-N-乙酰葡糖胺作为糖基部分的“来源”。获得了比其他人先前报道的更高量的[¹⁴C]N-乙酰葡糖胺掺入几丁质的情况。以与体内合成类似的方式确认了产物的身份。在几丁质合成的同时，在脂溶性部分也发现了放射性。该化合物具有阴离子行为，对酸不稳定，并且具有与用猪肝提取物获得的焦磷酸多萜醇N-乙酰葡糖胺相似的色谱性质。关于真核生物中多萜醇磷酸糖介导的糖蛋白合成的知识表明，即使在昆虫中，这种类型的N-乙酰葡糖胺基磷脂也参与大分子“构建”。
